With reference to FIG. 1, a typical tri cone drill bit is shown which includes a main body portion with a generally cylindrical outer surface which includes a threaded portion (not shown) by which the drill bit is connected to the end of a drill string (not shown).
Extending from the main body 12 in an axial downward direction (although FIG. 1 shows the drill bit in the reversed orientation), are three legs equally spaced about a central longitudinal axis of the main body portion.
The three legs are connected to three conical cutter elements which are able to rotate relative to the legs which are fixed with respect to the main body portion. The conical cutting elements are typically provided with several rows of teeth.
Inspection of drill bits during operational life has consistently shown that the flow of air and fragmented material must take a specific path in order to exit from under and then around the bit.
The present invention seeks to provide a drill bit which facilitates the removal of fragmented material from under the drill bit and hence provide a drill bit which provides increased efficiency during the drilling operation.